Sound pressure box

ABSTRACT

A sound pressure box for testing hearing aids and other devices is provided with a support member having a reference area onto which the hearing aid or device to be tested is disposed. A support frame for the sound-generating means is positioned within a bottom section of the box at about a forty five degree angle so that the axis of the sound-generating means is not coincident with the reference area.

f 2/3 l-IPSllQ xe 3,923,1w United Stat i [111 3,923,119

Frye 1 Dec. 2, 1975 [5 SOUND PRESSURE BOX 2.803.128 8/1957 Petermann 73/671 2.806.544 9/1957 Witchry 179/1751 A [76] Inventor: George Joseph Frye, 12175 SW. Douglas, Portland, Oreg. 97225 [22] Filed: Jan. 3, 1974 [21] Appl No.: 430,463

Primary Examiner-Maynard R. Wilbur Assistant ExaminerN. Moskowitz 57 I ABSTRACT [52] U.S. Cl 181/5; 181/33 R; 181/136;

73/432; 179/1 R; l79/175 1 A A sound pressure box for testing hearing aids and 51 Int. cl. GOlV 1/00 other devices is Provided with a support member [58] Field of Searchmu 79/1 R l E l N 175 1 A ing a reference area onto which the hearing aid or de- 179/180; 73/10 V, 69 553 4 A, 432 B vice to be tested is disposed. A support frame for the 432 D 181/136, 33 R, R sound-generating means is positioned within a bottom section of the box at about a forty five degree angle so [56] References Cited that the axis of the sound-generating means is not c0- UNITED STATES PATENTS incident with the reference area.

2.782.632 2/1957 Klein et a1. 73/69 6 Claims, 1 Drawing Figure U.S. Patent Dec. 2, 1975 3,923,119

FIG. 1

sou D PRESSURE Box BACKGROUNDOE HE Nv NTIoN' This invention is related to a sound pressure box and more particularly "to a sound-pressure box for testing hearing aids and other devices wherein the sound generating means is mounted such that it's'axis is offset with respect to theaxis of the box or sound chamber therein.

Sound pressure boxes are known wherein the soundgenerating means is mounted therein such that the axis of the soundgenerating means is coincident with the axis of the box or the sound'chamber thereinQIn' this conflguration, the sound emanating from the soundgenerating means impinges directly onto the device to be tested and a portion thereof reflects off to the device back onto the sound-generating means thereby adding to or substracting from the amplitude of the signal being generated by the sound-generating means. This constitutes interference with the truesignal being generated and makes it difficult to test the device to be tested in the presence of the undesired signalsthat have been propagated.

An object of the present invention is to provide a sound chamber box wherein the undesired signals are minimized and a more accurate test can be conducted on the device to be tested.

Another object of the present invention is the provision of a sound chamber box having means mounting a sound-generating means at an angle with respect to the vertical axis of the box so that the sound generated by the sound-generating means does not impinge directly on the device to be tested.

A further object of the present invention is to provide a sound chamber box wherein the mounting means for the sound-generating means is mounted in said box at about a forty five degree angle so that the soundgenerating means is disposed at about 45 relative to the vertical axis of the sound chamber box.

An additional object of the present invention is the provision of a mounting means for the soundgenerating means of a sound chamber box extending between opposed sides of the box and affixed thereto in order to maintain the mounting means in position and to stiffen the sides of the box thereby attenuating unwanted sound external of the sound chamber box.

A still further object of the present invention is to provide a sound chamber box wherein an open space is provided at an inner end of the mounting means for the sound-generating means to extend the bass or low frequency response of the sound pressure chamber and -to enable a more compact or smaller chamber to be used.

Still an additional object of the present invention is the provision of a reference area on the device mounting means which is offset with respect to the soundgenerating means axis in order to make certain that the sound reflected off the device to be tested reflects at an angle and can be attenuated more readily.

A still another object of the present invention is to provide retaining means extending between the device mounting means and the mounting means for the sound-generating means to retain the accousticaldamping material in position and provide an open area between the sound generating means and the area of the device mounting means containing the reference area.

.ERIEFDE's'c RIPTIoN OF THE DRAWING In the accompanyingdrawing,-FIG. 1 is a crosssectional view of a sound-pressure box illustrating the features of the present invention.

DETAILED DESCRIPTION OF THE INvENTIoN Turning now to FIG. 1, a sound pressure box SPB is shown in cross'section. It is divided into a bottom section 10 and a top section 12, which are hingedly mounted together via hinges 14 toenable top section 12 to be opened and c'lOsedJThe box can be made of metal, wood or other structurial material. A screen material 16 is secured onto the inner edges of top section 12 to maintain sound-absorbing material 18 in position therein. Such sound-absorbing material can be glass wool or other material having the desired soungabsorbing capability. t

A support frame 20 is made from heavy guage screen material and it is positioned on mounting members 22 secured onto the inner walls of bottom section 10 adjacent the upper edges thereof. Support frame 20 has a centrally-disposed dished area 21 provided with a reference area 24. Devices to be tested. such as hearing aids, are positioned at reference area 24. An acoustically transparent material 26 is secured onto support frame 20 and it has a reference area 28 coincident with reference area 24.

A mounting member 30 is secured between opposing sides of bottom section 10 and extends from the upper end to a position spaced from the inner end and it is disposed at a 45 angle within the bottom section as shown. An opening 32 is centrally located in mounting member 30 and a sound-generating means 34 is secured to the inner surface of mounting member 30 surrounding opening 32. Sound-generating means 34 is preferably a speaker connected to appropriate electronic circuitry (not shown) for operating same. The fact that mounting member 30 is secured to opposing sides of bottom section 10 stiffens the sides of bottom section 10 thereby attenuating of unwanted sounds external to the soundpressure box. The open space between the inner end of mounting member 30 and the inner wall of bottom section 10 forms a port which can be tuned in the same manner as a bass reflex enclosure for a speaker in order to extend the bass or low frequency response of the sound pressure chamber. This features enables a more compact and smaller box to be used with equivalent operation to that of a conventional large sound-pressure box.

If desired, mounting member 30 can extend the full diagonal length of bottom section 10 and be provided with an opening at itsinner end to provide the port.

Sound-absorbing material 18 is positioned within the voids of bottom section 10 and annular screen 36 extends between dished area 21 and mounting member 30 surrounding opening 32 to provide open area between sound-generating means 34 and the dished area 21.

By mounting sound-generating means 34 at or about a forty five degree angle within the sound-pressure box, the reflected sound waves generated thereby follow a relatively long multiple reflective path before becoming coincident and reinforcing the incident sound waves which multiple reflective path results in the reflected sound waves being largely absorbed in the attenuating material.

Reference area 24, 28 is provided in dished area 21 so that a hearing aid or device to be tested is positioned thereat. Reference area 24, 28 is offset with respect to the sound-generating means axis and this will result in the reflections from the hearing aid case or case of the device to be tested or from parts of the support frame to impinge on the soundgenerating means and mounting member 30 at an angle such that re-reflection therefrom will pass into an area different from that at which the hearing aid or device to be tested is posi-. tioned. This will enable the hearing aid or device to be tested to provide a response substantially independent of unwanted reflectively caused amplitude peaks thereby resulting in a more true test of the hearing aid or device to be tested at the selected frequencies.

Although, the invention has been explained with reference to a particular embodiment, it is to be appreciated that various adaptations and modifications may be made without departing from the appended claims.

The invention is claimed in accordance with the following:

l. A sound pressure box comprising:

a top section;

a bottom section;

means connecting said top section and said bottom section together;

sound-absorbing material disposed in said top section and said bottom section;

device-holding means mounted in said bottom section; mounting means disposed in said bottom section extending between an upper end of said bottom section and an opposed inner end thereof; and

sound-generating means mounted on said mounting means so that the axis thereof is at an angle with respect to the vertical axis of said box.

2. A sound-pressure box according to claim 1 wherein said mounting means is disposed at about a 45 angle.

3. A sound pressure box according to claim 1 wherein said mounting means has its inner end spaced from said opposed inner end to provide a space therebetween. i

4 A sound pressure box according to claim 1 wherein said mounting means is secured to opposite sides of said bottom section to stiffen said opposite sides.

5. A sound pressure box according to claim 1 wherein said device holding means has a dished area in which a device to be tested is disposed.

6. A sound pressure box according to claim 5 wherein said dished area is provided with a reference area at which the device to be tested is disposed. 

1. A sound pressure box comprising: a top section; a bottom section; means connecting said top section and said bottom section together; sound-absorbing material disposed in said top section and said bottom section; device-holding means mounted in said bottom section; mounting means disposed in said bottom section extending between an upper end of said bottom section and an opposed inner end thereof; and sound-generating means mounted on said mounting means so that the axis thereof is at an angle with respect to the vertical axis of said box.
 2. A sound-pressure box according to claim 1 wherein said mounting means is disposed at about a 45* angle.
 3. A sound pressure box according to claim 1 wherein said mounting means has its inner end spaced from said opposed inner end to provide a space therebetween.
 4. A sound pressure box according to claim 1 wherein said mounting means is secured to opposite sides of said bottom section to stiffen said opposite sides.
 5. A sound pressure box according to claim 1 wherein said device holding means has a dished area in which a device to be tested is disposed.
 6. A sound pressure box according to claim 5 wherein said dished area is provided with a reference area at which the device to be tested is disposed. 